Avaliação de parâmetros fotossintéticos em microplantas de Castanheiro durante a fase de aclimatização.
Type
article
Creator
Identifier
GONÇALVES, J.C. ; COELHO, M.T. ; DIOGO, M.G. (2014) - Avaliação de parâmetros fotossintéticos em microplantas de Castanheiro durante a fase de aclimatização. Agroforum : Revista da Escola Superior Agrária de Castelo Branco. ISSN 0872-2617. Ano 22:32, p. 27-40.
0872-2617
Title
Avaliação de parâmetros fotossintéticos em microplantas de Castanheiro durante a fase de aclimatização.
Subject
Aclimatização
Castanheiro
Fotossíntese
Irradiância
Rizogénese
Acclimatization
Chestnut
Light intensity
Photosynthesis
Rooting
Castanheiro
Fotossíntese
Irradiância
Rizogénese
Acclimatization
Chestnut
Light intensity
Photosynthesis
Rooting
Date
2018-02-17T16:42:17Z
2018-02-17T16:42:17Z
2014
2018-02-17T16:42:17Z
2014
Description
O objetivo deste trabalho foi realizar um estudo comparativo em microplantas de castanheiro com dois sistemas de expressão e desenvolvimento radicular, in vitro e ex vitro, e com duas intensidades luminosas (150 e 250 μmol m-2 s-1) durante a aclimatização, e a sua influência no desenvolvimento das microplantas durante esta fase, através da quantificação de parâmetros fotossintéticos. A concentração de clorofilas, após os tratamentos de aclimatização, dependeu quer do tipo de sistema radicular que as plantas possuíam no início da aclimatização, quer do regime luminoso a que as plantas estiveram submetidas.
As plantas com enraizamento in vitro e aclimatizadas sob menor irradiância foram as que apresentaram valores superiores para a clorofila total (7,74 mg g-1ps), mas com o valor mais baixo na razão entre clorofila a/b (2,7).
Quando comparamos os valores registados para os parâmetros fotossintéticos das plantas dos diferentes tratamentos, verificamos que as taxas de fotossíntese aparente vão gradualmente aumentando à medida que as novas folhas se vão desenvolvendo (0,75 μmol CO2 m-2 s-1 nas folhas persistentes e 3,43 μmol CO2 m-2 s-1 na folha 3 das plantas aclimatizadas a 250 μmol m-2 s-1). O mesmo acontece na capacidade fotossintética (3,93 μmol O2 m-2 s-1 nas folhas persistentes e 7,87 μmol O2 m-2 s-1 na folha 3 das plantas aclimatizadas a 250 μmol m-2 s-1). Estes valores foram tendencialmente superiores nas plantas com enraizamento ex vitro e aclimatizadas a maior irradiância, pelo que a um melhor sistema radicular e uma maior disponibilidade luminosa correspondeu um acréscimo na competência fotossintética, o que resultou num melhor desenvolvimento morfofisiológico das plantas.
Abstract The aim of this study was to conduct a comparative study in chestnut microplants with two systems of expression and root development, in vitro and ex vitro, and with two light intensities (150 and 250 μmol m-2 s-1) during acclimatization, and its influence on the development of microplants during this phase, through the quantification of photosynthetic parameters. The chlorophyll concentration after acclimatization treatments depended on both type of root system that the plants had at the beginning of acclimatization, whether the light intensity to which the plants were subjected. Plants with roots in vitro and acclimatized under lower irradiance showed the higher values for total chlorophyll (7.74 mg g-1ps), but with the lowest value of the ratio of chlorophyll a/b (2.7). When the values recorded for the photosynthetic parameters of plants of different treatments were compared, we found that the rates of apparent photosynthesis gradually increasing as the new leaves are developed (0.75 μmol CO2 m-2 s-1 in persistent leaves and 3.43 μmol CO2 m-2 s-1 on leaf 3 on plants acclimatized to 250 μmol m-2 s-1). The same happens in photosynthetic capacity (3.93 μmol O2 m-2 s-1 in persistent leaves and 7.87 μmol O2 m-2 s-1 on leaf 3 of plants acclimatized to 250 μmol m-2 s-1). These values were higher in plants with ex vitro rooting and acclimatization to higher irradiance, so a better root system availability and a higher light availability, corresponding to an increase in the photosynthetic ability, resulting in a better morphophysiological plant development.
info:eu-repo/semantics/publishedVersion
Abstract The aim of this study was to conduct a comparative study in chestnut microplants with two systems of expression and root development, in vitro and ex vitro, and with two light intensities (150 and 250 μmol m-2 s-1) during acclimatization, and its influence on the development of microplants during this phase, through the quantification of photosynthetic parameters. The chlorophyll concentration after acclimatization treatments depended on both type of root system that the plants had at the beginning of acclimatization, whether the light intensity to which the plants were subjected. Plants with roots in vitro and acclimatized under lower irradiance showed the higher values for total chlorophyll (7.74 mg g-1ps), but with the lowest value of the ratio of chlorophyll a/b (2.7). When the values recorded for the photosynthetic parameters of plants of different treatments were compared, we found that the rates of apparent photosynthesis gradually increasing as the new leaves are developed (0.75 μmol CO2 m-2 s-1 in persistent leaves and 3.43 μmol CO2 m-2 s-1 on leaf 3 on plants acclimatized to 250 μmol m-2 s-1). The same happens in photosynthetic capacity (3.93 μmol O2 m-2 s-1 in persistent leaves and 7.87 μmol O2 m-2 s-1 on leaf 3 of plants acclimatized to 250 μmol m-2 s-1). These values were higher in plants with ex vitro rooting and acclimatization to higher irradiance, so a better root system availability and a higher light availability, corresponding to an increase in the photosynthetic ability, resulting in a better morphophysiological plant development.
info:eu-repo/semantics/publishedVersion
Access restrictions
openAccess
http://creativecommons.org/licenses/by/4.0/
http://creativecommons.org/licenses/by/4.0/
Language
por
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